Is there a similar example that we can see? But now I got this: hidden link - 3 slides underneath. Do You have another better video or documentation I can follow?
Unfortunately we don't have any other documentation on how to create the carousels. However if it is simply a case where you want to have 3 posts rather than 1 you can just use the Pagination setting at 3:00 minutes into the video and set it to 3 rather than 1.
This should give you 3 items per page when the slider paginates.